Schrodinger's Cat was intended as a thought experiment as to why Quantum Mechanics was ridiculous when applied to macroscopic objects - one way to tell if someone actually understands it is if they know of/proved Ehrenfest's Theorem, which says that Quantum Mechanics statistically averages out to Newtonian Mechanics. This happens to be quite useful in not invalidating basically all engineering knowledge, but nobody who uses quantum physics to justify reality warping seems to be aware of any of that.
I think it's equal parts sloppy fact checking and simply struggling to find any version of A Wizard Did It that can actually work for a science-fiction series. There's still lots of mystery about exactly why quantum effects don't appear in everyday life, and theories like Many-worlds and wave-function collapse are so bizarre and seemingly mind-driven that they're an easy way to reproduce all the random, plot-driven craziness of magic in a scientific setting.
An excellent layman's guide to the (non mystical) strangeness of quantum behavior is this.
Schrodinger's cat is just a thought experiment, which doesn't work in the real world because when you use quantum mechanics to describe large (cat-sized) systems, it works exactly the same as classical mechanics (as shown in Ehrenfest's theorem). So what this basically means is that you can never get "quantum" effects, such as quantum tunneling ("walking through walls"), lack of interaction due to opposite phase ("cloaking/walking through walls"), or several states existing at the same time (Schrodiger's cat), on macroscopic scales. The misconception that quantum effects can somehow exist in the real world is an excuse many people use to justify reality bending (or ghosts, souls, homeopathy, etc.).
To be fair, we cannot be sure of ANYTHING about this right now, because the current theory is also lacking "something" in order to work perfectly, and that's why there is a lot of other theories by the way. So both sides can argue just like they want to, anyone still have a slight chance to be right. To sum it up, the cat experiment is here to show that we are okay with particles having two states in the same time, but it is harder to accept it with real things. The cat was not supposed to be "dead and alive" when the theory was created, it was supposed to be "impossible" in the macroscopic world, period. But the catbox doesn't prove anything about quantum and macroscopic physics at all, and doesn't explain anything. You'll have to look at other theorems if you want to see how to solve the quantum physics != macroscopic physics.
this could be justified in the character in questions actual power being probability altering (Ala scarlet witch,) this would allow them to change the probability of quantum affects on the macro scale, still ridiculous but it makes more sense,
The problem with the concept of "probability alteration" is that it's fundamentally putting the cart before the horse. Probabilities are part of the mathematical model used to describe a given phenomenon; to properly affect them, you essentially need whatever powers it takes to actually alter the reality underlying the model anyway. (This doesn't necessarily even require all-out reality warper power levels. I could in theory develop the power of "probability alteration" over such things as dice or cards simply by learning some sleight of hand, for example.)